Sex is a big part of teen soap operas like Fox's popular “The OC.” Two-thirds of American TV shows include some sexual content. (Fox Broadcasting Co.)

Teen-pregnancy rates have declined significantly since 1991. However, American teenagers have more pregnancies, births and abortions than youngsters in other industrialized countries. And 4 million teens contract a sexually transmitted disease each year. While U.S. high-schoolers increasingly are either postponing intercourse or using contraception, recent media reports highlight a potentially disturbing trend: Many middle- and high-school students say they are engaging in casual oral sex. Conservatives credit abstinence-only sex education for the pregnancy-rate decline while liberals tout comprehensive programs that promote abstinence while also providing information about contraception. The federal government only funds abstinence education, even though at least 75 percent of parents say they want teens to be taught about both abstinence and contraception. But today fewer American schools are teaching comprehensive sex education, and about a third of U.S. public high schools have switched to abstinence-only sex ed.